Catheter system

ABSTRACT

A catheter system includes an elongate catheter having a lumen extending at least partially therethrough, and a leading catheter end segment, a guidewire positionable within the lumen of the catheter, and fastening structure supported adjacent the leading catheter end segment. The guidewire and the catheter are adapted for relative movement. The fastening structure is dimensioned to selectively engage the guidewire to secure the guidewire with respect to the leading catheter end segment such that movement of the guidewire causes deflection of the leading end segment with respect to the longitudinal axis.

BACKGROUND

1. Technical Field

The present disclosure relates generally to medical systems and methodsand, more particularly, relates to a steerable catheter system for usein an intravascular procedure.

2. Description of Related Art

Catheters are well known in the art. A catheter generally consists of anelongated, flexible tubular body defining at least one lumen extendingtherethrough. Catheters may be tracked along a previously positionedguidewire in the vasculature. The lumen provides a conduit for deliveryof instrumentation or material to or from the body, or for the deliveryof medical devices to a treatment site. Catheters may incorporatesteering mechanisms permitting the clinician to deflect or manipulatethe leading end of the catheter to navigate the often tortuous path ofthe vasculature. However, the steering mechanisms generally increase thecross-sectional dimension of the catheter, thus limiting the use of thecatheters in certain procedures.

SUMMARY

The present disclosure is directed to improvements in steerablecatheters. The catheter or medical system disclosed herein incorporatesvarious mechanisms that engage a conventional guidewire with the leadingend segment of a catheter. Once engaged the guidewire is manipulated todeflect the leading end segment of the catheter. Manipulation of theleading catheter end segment provides a low profile and selectivelysteerable catheter system for advancement within the vasculature.

In embodiments, a catheter system includes an elongate catheter defininga longitudinal axis having a lumen extending at least partiallytherethrough and a leading catheter end segment, a guidewirepositionable within the lumen of the catheter, and a fastening structuresupported adjacent the leading catheter end segment. The guidewire andthe catheter are adapted for relative movement. The fastening structureis dimensioned to selectively engage the guidewire to secure theguidewire with respect to the leading catheter end segment such thatmovement of the guidewire causes deflection of the leading end segmentwith respect to the longitudinal axis.

The catheter may include a clamp adjacent the leading catheter endsegment. The clamp is movable between a first position corresponding tothe release condition of the guidewire and a second positioncorresponding to the secured condition of the guidewire where the clampengages the guidewire in the lumen in secured relation therewith. Inembodiments, the clamp is at least partially disposed within the lumenof the catheter when in the secured condition of the guidewire relativeto the catheter. In embodiments, the clamp is a grommet defining apassage for reception of the guidewire. The grommet may be at leastpartially compressible to engage the guidewire upon movement to theactuated position. In embodiments, the grommet is adapted to move withinthe lumen from a first longitudinal position to a second longitudinalposition in response to introduction of fluids within the lumen. Thecatheter may include internal tapered surfaces adjacent the lumen withthe tapered surfaces cooperating with the grommet during movementthereof to the second longitudinal position to compress the grommet ontothe guidewire. A source of pressurized fluids may be in fluidcommunication with the lumen.

In embodiments, the catheter includes at least one expandable memberwithin the lumen. The at least one expandable member is adapted totransition between an initial condition corresponding to the releasecondition of the guidewire and an expanded condition corresponding tothe secured condition of the guidewire in which the at least oneexpandable member engages the guidewire in secured relation therewith.The at least one expandable member may be a balloon member. Inembodiments, the catheter includes an inflation tube extending throughthe lumen in fluid communication with the balloon member. Alternatively,the catheter defines a second lumen, which is an inflation lumen, and isin fluid communication with the balloon member.

In embodiments, a filament member extends along the catheter and definesa loop segment. The loop segment is dimensioned to receive the guidewireto secure the guidewire relative to the catheter to establish thesecured condition of the guidewire relative to the catheter. The loopsegment may include a lasso.

In embodiments, the catheter includes a device lumen dimensioned forreception of an interventional device.

In embodiments, the catheter includes a second lumen and a drivedisposed within the second lumen. The drive is adapted for longitudinalmovement within the second lumen from a first longitudinal position to asecond longitudinal position to cause deflection of a wall surface ofthe first-mentioned lumen such that the wall surface engages theguidewire in secured relation thereby achieving the secured condition ofthe guidewire. The catheter may define an internally tapered surfaceadjacent the leading end thereof and at least partially defining thesecond lumen. The drive element may deflect towards the first-mentionedlumen upon traversing the tapered surface to cause deflection of thewall surface to drive the guidewire against an opposed internal wallsurface of the first lumen.

In embodiments, the guidewire may be adapted for one of rotational orradial movement relative to the catheter to cause deflection of theleading catheter end segment.

In embodiments, the catheter may include first and second lumens and theleading catheter end segment having first and second catheter sections.First and second guidewires are positionable within the first and secondlumens of the catheter. Each of the first and second guidewires isadapted for relative movement within the respective first and secondlumens. First fastening structure is dimensioned to selectively engagethe first guidewire to secure the first guidewire with respect to thefirst catheter section such that movement of the first guidewire causesdeflection of the first catheter section and second fastening structureis dimensioned to selectively engage the second guidewire to secure thesecond guidewire with respect to the second catheter section such thatmovement of the second guidewire causes deflection of the secondcatheter section. The first catheter section may be adapted to deflectin a first radial direction with respect to the longitudinal axis andthe second catheter section may be adapted to deflect in a second radialdirection with respect to the longitudinal axis. The first radialdirection may be different from the second radial direction.

In embodiments, the fastening structure and the guidewire each includeferromagnetic material. The fastening structure may include anelectromagnet selectively activated by an electric current.

In embodiments, the guidewire includes a looped segment, and thecatheter includes at least one detent depending into the lumen. Thedetent is positioned to engage the looped segment of the guidewire tosecure the guidewire with respect to the leading catheter end segment.

In embodiments, the leading catheter end segment includes lockingstructure of predefined geometry within the lumen and the guidewireincludes a locking element. The locking element is adapted to movebetween release and secured conditions with respect to the leadingcatheter end segment through relative rotation of the guidewire and theleading catheter end segment about the longitudinal axis.

In embodiments, a catheter system includes an elongate catheter having alumen extending at least partially therethrough and a leading catheterend segment, a guidewire positionable within the lumen of the catheterand fastening structure supported adjacent the leading catheter endsegment. The fastening structure is movable between initial and actuatedpositions thereof corresponding to respective release and coupledconditions of the guidewire relative to the leading catheter endsegment. In the release condition, the guidewire and the catheter arecapable of relative longitudinal movement. In the coupled condition, theguidewire and the leading catheter end segment are secured such thatlongitudinal movement of the guidewire causes deflection of the leadingcatheter end segment with respect to the longitudinal axis.

A medical method is also disclosed. The method includes introducing aguidewire within vasculature of a subject; advancing a catheter alongthe guidewire; securing the guidewire adjacent a leading end segment ofthe catheter; and manipulating the guidewire to cause deflection of theleading end segment of the catheter. Securing the guidewire may includeselectively securing and releasing the guidewire relative to the leadingend segment of the catheter. Securing the guidewire may be performedsubsequent to advancing the catheter. The method may further includeperforming an interventional procedure. Performing the interventionalprocedure includes introducing a medical interventional device withinthe catheter.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentdisclosure will become more apparent in light of the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 illustrates a view of the catheter system in accordance with theprinciples of the present disclosure illustrating a catheter and aguidewire positionable within the catheter;

FIG. 2 is a side cross sectional view of the leading catheter endsegment of the catheter of the catheter system of FIG. 1;

FIG. 3 is a cross-sectional view of the catheter taken along the lines3-3 of FIG. 2;

FIG. 4 is an enlarged view of the area of isolation designated in FIG. 3illustrating the grommet positioned within the guidewire lumen of thecatheter and in a first position;

FIG. 5 is a view illustrating the catheter and the guidewire positionedwithin vasculature.

FIG. 6 is a side cross-sectional view similar to the view of FIG. 2illustrating the grommet in a second position securing the guidewirerelative to the leading catheter end segment;

FIG. 7 is an enlarged view of the area of isolation 7 designated in FIG.6 illustrating the grommet in the second position;

FIG. 8 is a view illustrating flexing of the leading catheter endsegment upon movement of the guidewire in a longitudinal direction;

FIG. 9 is a side cross-sectional view of an embodiment of the catheterincorporating an expandable member in the guidewire lumen and in aninitial condition;

FIG. 10 is a view similar to the view of FIG. 9 illustrating theexpandable member in an expanded condition securing the guidewirerelative to the leading catheter end segment;

FIG. 11 is a side cross-sectional view of an alternate embodiment of thecatheter of FIGS. 9-10, incorporating a separate inflation tubeextending through the guidewire lumen;

FIG. 12 is a side cross-sectional view of an embodiment of the catheterincorporating a filament loop adjacent the guidewire lumen;

FIG. 13 is a view similar to the view of FIG. 12 illustrating thefilament loop securing the guidewire relative to the leading catheterend segment;

FIG. 14 is a side cross-sectional view of an embodiment of the cathetermember incorporating a drive member with the drive member in a firstposition corresponding to a release condition of the guidewire;

FIG. 15 is a view similar to the view of FIG. 14 illustrating the drivemember in a second position corresponding to a secured condition of theguidewire;

FIG. 16 is a side cross-sectional view of another embodiment of thecatheter member incorporating an electromagnet in an initial conditioncorresponding to a release condition of the guidewire;

FIG. 17 is a view similar to the view of FIG. 16 illustrating theelectromagnet in an actuated condition corresponding to a securedcondition of the guidewire;

FIG. 18 is a side cross-sectional view of another embodiment of thecatheter member incorporating first and second guidewires andcorresponding first and second fastening structures for securingproximal and distal sections of leading catheter end segment of cathetersystem shown in FIG. 1;

FIG. 19 is a side cross-sectional view of another embodiment of thecatheter member incorporating a looped segment of the guidewire anddepicting a release condition of the guidewire;

FIG. 20 is a view similar to the view of FIG. 19 illustrating the loopedsegment engaged with at least one locking detent of the catheter memberdepicting a secured condition of the guidewire;

FIG. 21 is a side cross-sectional view of another embodiment of thecatheter member incorporating a guidewire having a lock element and thecatheter having corresponding lock structure, and depicting a releasecondition of the guidewire;

FIG. 22 is an enlarged axial cross-sectional view illustrating theguidewire rotated relative to the catheter member whereby the lockelement of the guidewire and the lock structure of the catheter memberare engaged depicting a secured condition of the guidewire; and

FIG. 23 is a flow chart illustrating an exemplary use of the system inan intravascular procedure.

DETAILED DESCRIPTION

In the following description, the term “proximal” refers to the end ofthe system extending outside the body closest to the clinician. The term“distal” or “leading” refers to the end or segment of the system remotefrom the clinician.

The system of the present disclosure has particular application inneurovascular procedures, but may also be used in any interventional,diagnostic, and/or therapeutic procedure including coronary vascular,peripheral vascular and gastrointestinal applications.

The system includes a catheter and a guidewire. The catheter may havevarious mechanisms adapted to selectively engage the guidewire along aleading catheter end segment of the catheter, and, in some embodimentsalong various longitudinal locations along the leading catheter endsegment. In embodiments, the guidewire is introduced into thevasculature and the catheter is advanced along the guidewire.Thereafter, the catheter is coupled to the guidewire adjacent theleading end segment. In this engaged relation, the guidewire may beretracted or rotated causing the leading catheter end segment to deflector bend to a desired orientation. The guidewire provides steeringcapabilities to the catheter system without necessitating the use ofpull wires or other mechanisms within the catheter. This maysignificantly reduce the profile of the catheter and maximize the sizeof a second or device lumen, which receives an interventional device.

Referring now to FIG. 1, the system 1 of the present disclosure isillustrated and includes a catheter 10 and a guidewire 100. The catheter10 may be a microcatheter adapted for use in neurovascular procedures.The catheter 10 includes a catheter hub 12 and an elongated cathetermember 14 extending from the catheter hub 12, and defining alongitudinal axis “k”. The catheter hub 12 may include a first port 16for introduction of a guidewire and a second port 18 for reception of aninterventional device. The catheter hub 12 also may include a third port20 for introduction of fluids used in conjunction with the variousmechanisms adapted to selectively engage the guidewire. Any of thefirst, second or third ports 16, 18, 20 may have a threaded segment 22to facilitate coupling to an auxiliary device such as a syringe and/or avacuum or aspiration source (not shown). The catheter hub 12 further mayinclude a strain relief 24, which is positionable over a segment of thecatheter member 14.

The catheter member 14 has a proximal end 26 and a leading catheter endsegment 28. The system 1 may further includes a fluid source 34 such assaline or any other atraumatic fluid which may be fluidly coupled to thethird port 20 of the catheter hub 12.

The catheter member 14 is dimensioned to access distal reaches of thevasculature and has sufficient flexibility to track along the guidewire100, which is previously introduced within the vasculature. The cathetermember 14 may be monolithically formed or may include multiple elementsor tubes assembled and connected to the catheter hub 12. Varyingsegments of flexibility may be incorporated within the catheter member14. For example, the catheter member 14 may have a relatively stiffsegment adjacent the proximal end 26 and less stiff regions toward theleading end 28. The catheter member 14 may include defined regions orsegments of flexibility or may gradually transition from a stifferregion to a less stiff region. The catheter member 14 may include abraid, a hypotube fabricated from materials including stainless steel,nitinol, nitinol alloys, or combinations thereof and/or a reinforcedpolymer tube. The braid may be fabricated from nitinol and have acontinuous pitch, or include multiple sections with different windingpitches. Marker bands (not shown) may be embodied within the cathetermember 14 adjacent the leading end segment 28 to assist in visualizationof the catheter member 14 during implantation within the vasculature.

The guidewire 100 may be any conventional guidewire. In accordance withone application of the present disclosure, the maximum outer diameter ofthe guidewire ranges from about 0.008 inches (0.20 millimeters) to about0.018 inches (0.46 millimeters). These diameters are standard forguidewires used, e.g., in a neurovascular procedure. Other diameters arecontemplated for cardiovascular, peripheral vascular andgastrointestinal applications. The diameter of the guidewire may remainrelatively constant over a major portion of the length of the guidewire.In the alternative, the leading or distal end incorporates a generallytapered or narrowed configuration to permit flexure while navigating thetortuous vasculature. The guidewire 100 may include a number of taperedsegments, which may or may not be continuous. The length of theguidewire 100 may range from about 30 (760 millimeters) to about 400inches (10,165 millimeters). Other lengths are also contemplated.

Referring now to FIGS. 2 and 3, in conjunction with FIG. 1, a firstguidewire lumen 30 extends the length of the catheter member 14 and isin communication with the first port 16 for reception and passage of theguidewire 100. The third port 20 may be in fluid communication with theguidewire lumen 30. The catheter member 14 may define a device lumen 32in communication with the second port 18 for passage of aninterventional device.

Referring now to FIG. 4, in conjunction with FIGS. 1 and 2, oneembodiment for securing the guidewire 100 to the catheter 10 to providesteering or deflecting capabilities to the catheter 10 is illustrated.In accordance with this embodiment, the system further includes a fluidsource 34 such as saline or any other atraumatic fluid which may befluidly coupled to the third port 20 of the catheter hub 12. Thecatheter member 14 includes a compressible clamp such as a grommet 36positionable within the guidewire lumen 30 adjacent a leading catheterend segment 28 of the catheter member 14. The grommet 36 may be formedof any compressible resilient material including foam, a gel material,polyisoprene or the like. The grommet 36 defines an opening 40 to permitpassage of the guidewire 100 when the grommet 36 is in the position ofFIG. 4. The catheter member 14 defines opposed internal surfaces 42adjacent the leading end 28, which taper radially inwardly relative tothe longitudinal axis “k” toward the leading end 28 of the cathetermember 14. In the first position of the grommet 36 as depicted in FIGS.2 and 4, the catheter 10 may track along the guidewire 100. This firstposition of the grommet 36 corresponds to the disengaged or releasedcondition of the guidewire 100 relative to the catheter member 14.

In use, and with reference to FIG. 5, which is a view representative ofvasculature “v” of the subject, e.g., the neurovasculature, theguidewire 100 is positioned within the vasculature to access anintravascular site. The catheter 10 is advanced along the guidewire 100within the guidewire lumen 30 of the catheter member 14 and through theopening 40 in the grommet 36. The catheter 10 is advanced along theguidewire 100 within the vasculature “v” with the leading catheter endsegment 28 adjacent the targeted site.

With reference to FIGS. 5-7, in conjunction with FIG. 1, the fluid “f”from the fluid source 34 is delivered under pressure into the third port20 to communicate with the guidewire lumen 30. In the alternative, thefluids “f” may be introduced within the first port 16 even in thepresence of the guidewire 100 extending out from the first port 16. Thefluid “f” drives the grommet 36 distally toward the leading catheter endsegment 28 from the first position depicted in FIGS. 2 and 4 to thesecond position of the grommet 36 depicted in FIGS. 6 and 7. As thegrommet 36 is driven toward the second position, the internal taperedsurfaces 42 of the catheter member 14 cooperate to compress the grommet36 such that the grommet 36 engages the guidewire 100 in securedrelation therewith as best depicted in FIG. 7. The catheter member 14may incorporate proximal and distal internal stops 44, 46 to limitmovement of the grommet 36 within the guidewire lumen 30. The secondposition of the grommet 36 corresponds to the secured condition of theguidewire 100 relative to the leading catheter end segment 28. Thefluids “f” may be continually supplied to the guidewire lumen 30 therebymaintaining continued pressure on the grommet 36. With the grommet 36securely engaged to the guidewire 100 adjacent the leading catheter endsegment 28 of the catheter member 14, the guidewire 100 is pulled in aproximal direction as shown by the directional arrows “m” of FIG. 8,which causes the leading catheter end segment 28 to correspondinglydeflect relative to the longitudinal axis “k” in a direction “b”. Thedegree of deflection may be controlled by the amount of retraction ofthe guidewire 100. FIG. 5 depicts, in phantom, the leading catheter endsegment 28 in a deflected orientation within the vasculature “v”. Withthe leading catheter end segment 28 in the desired orientation, aninterventional device may be introduced through the second port 18 andinto the device lumen 32 of the catheter member 14 to perform a desiredintravascular procedure. Alternatively, controlling the degree ofdeflection enables the clinician to selectively engage and disengage theleading catheter end segment 28 to enable continued advancing movementof the catheter member 14 within the tortuous vasculature.

Once it is desired to disengage or release the leading catheter endsegment 28 from the guidewire 100, the supply of fluids “f” introducedwithin the first lumen 30 is halted, relieving the distal pressure onthe grommet 36. The guidewire 100 may be pulled in the proximaldirection thereby displacing the grommet 36 toward the first position ofFIGS. 2 and 4, allowing guidewire 100 to freely move within guidewirelumen 30 again. The catheter member 14 may incorporate proximal anddistal stops 44, 46 to limit movement of the grommet 36 within the firstlumen 30. The catheter 10 may be further advanced along the guidewire100 or retracted as needed. Thus, the leading catheter end segment 28may be selectively secured and released relative to the guidewire 100via the aforedescribed movement of the grommet 36.

FIGS. 9-10 illustrate an alternate embodiment of the present disclosure.Catheter member 14 includes an expandable member 50 disposed within thefirst lumen 30. The expandable member 50 may be an inflatable balloonadapted to expand from the initial condition of FIG. 9 upon the passageof fluids from the fluid source 34 to within the internal chamber of theinflatable balloon 50, to the inflated condition illustrated in FIG. 10.An inflation conduit extends from the first or third port 16, 20 and isin fluid communication with the inflatable balloon. The conduit may be aseparate inflation lumen 54 in the catheter member 14 as depicted inFIG. 9 in fluid communication with the interior of the inflatableballoon through port 56 extending through the wall 58 of the cathetermember 14. In use, the catheter 10 is advanced along the previouslypositioned guidewire 100 within the vasculature. When the leadingcatheter end segment 38 is at the target site within the vasculature,inflation fluids are supplied from the fluid source 34 through eitherthe first or third ports 16, 20 to pass through the fluid conduit suchas the inflation lumen 54, for delivery through the port 56 and into theinflatable balloon to expand the inflatable balloon to the expandedcondition depicted in FIG. 10. In the expanded condition, the inflatableballoon engages the guidewire 100 and secures the guidewire 100 relativeto the inner surfaces 62 defining the first lumen 30 of the cathetermember 14. Thereafter, the guidewire 100 is pulled in a proximal ortrailing direction while the catheter 10 is held stationary causing theleading catheter end segment 38 to deflect as depicted in FIG. 8.

FIG. 11 depicts an alternate embodiment in which the separate inflationlumen 54 is eliminated. Fluid is conveyed to the inflatable balloon fromthe fluid source 34 through a tube 60 (shown schematically) whichextends within the first lumen 30.

FIGS. 12-13 illustrate another embodiment incorporating a filament loop70 for engaging the guidewire 100 to the catheter member 14. Thefilament loop 70 includes an elongated filament segment 72 and a loopsegment 74. The filament segment 72 may extend through a third lumen 76of the catheter member 14 or alternatively extend through the devicelumen 32 thereby obviating the need for the third lumen 76. The loopsegment 74 is positioned within or in general alignment with the firstlumen 30 and extends through the interior wall 78 of the catheter member14 for reception within the third lumen 76. The filament loop 70 mayinclude a sliding knot or lasso forming the loop segment 74 which can betied about the guidewire 100 by applying tension to the filament segment72. Various known suture-lassoing techniques may be incorporated intothe filament loop 70. In use, the guidewire 100 is advanced though thevasculature. The catheter member 14 is tracked along the guidewire 100with the guidewire 100 passing through the guidewire lumen 30. When theguidewire 100 has been threaded through the loop segment 74, thefilament segment 72 is pulled in the proximal direction (directionalarrow “m” in FIG. 13). The loop segment 74, which incorporates thesliding knot or a running noose, grasps the guidewire 100 drawing theguidewire 100 against the internal wall 78 of the catheter member 14. Inthis condition, the guidewire 100 is secured relative to the cathetermember 14. The guidewire 100 is moved in the proximal direction causingdeflection of the leading catheter end segment 28 in a similar mannerdiscussed hereinabove. In an alternate approach, the guidewire 100 maybe secured with the filament loop 70 relative to the catheter member 14prior to insertion of the guidewire 100 and the catheter member 14within the vasculature, and the combined unit simultaneously advancedwithin the vasculature.

FIGS. 14-15 illustrate another embodiment of the present disclosure. Inaccordance with this embodiment, the catheter member 14 includesguidewire lumen 80, a device lumen 82 and a third lumen 84. The thirdlumen 84 is dimensioned to receive a drive element 86, which is adaptedto reciprocate in a longitudinal direction within the third lumen 84. Anactuator 88 may be connected to the proximal end of the drive element 86for manual manipulation by the clinician to cause correspondinglongitudinal movement of the drive element 86. The internal surfacesdefining the third lumen 84 include a generally tapered surface 90adjacent the catheter leading catheter end segment 92. In use, theguidewire 100 is positioned within the vasculature and the cathetermember 14 is tracked along the guidewire 100 with the guidewire 100passing through the guidewire lumen 80. When it is desired to engage theguidewire 100 to the leading catheter end segment 92, the drive element86 is advanced from the first position depicted in FIG. 14 to the secondposition depicted in FIG. 15. Upon traversing the tapered surface 90,the leading end of the drive element 86 deflects towards the guidewirelumen 80, which causes the internal wall 94 of the lumen 80 tocorrespondingly deflect and drive the guidewire 100 against the opposedinternal wall 96 of the first lumen 80. In this position, the guidewire100 is wedged between the opposed internal walls 94, 96 and securedrelative to the catheter member 14. The guidewire 100 may be moved inthe trailing direction to accordingly deflect the leading catheter endsegment 92 in a similar manner shown in FIG. 8. To release the guidewire100, the actuator 88 and the drive element 86 are moved in the proximaldirection causing the leading end of the drive element 86 to return toits first position, thereby permitting the internal wall 94 to return toits first position depicted in FIG. 14.

FIGS. 16-17 illustrate another embodiment of the present disclosure. Inaccordance with this embodiment, the catheter member 14 includesguidewire lumen 120, a device lumen 122 and a third lumen 124. The thirdlumen 124 includes an electromagnet 126 adjacent the leading catheterend segment 128. The electromagnet 126 may be powered by an energysource 130 in communication with the electromagnet 126 via electricalwire 132 extending from the energy source 130 through the third lumen124. Alternatively, the electromagnet 126 may be powered via wirelesstechnology. The guidewire 100 may be fabricated at least in part offerromagnetic material such as steel, nitinol or other suitableferromagnetic metals or polymers. In the initial unactuated condition ofthe electromagnet 126, the guidewire 100 may traverse the first lumen120. Upon actuation of the electromagnet 126, the magnetic forces “f”thereby generated, will draw or deflect the guidewire 100 toward theelectromagnet 126 as depicted in FIG. 17. In this position, a segment ofthe guidewire 100 is secured against the internal wall 130 separatingthe guidewire lumen 120 and a third lumen 124.

In use, the guidewire 100 is positioned within the vasculature and thecatheter member 14 is tracked along the guidewire 100 with the guidewire100 passing through the guidewire lumen 120. When it is desired tosecure the guidewire 100 to the leading catheter end segment 128, theelectromagnet 126 is actuated. The magnetic forces “f” causes deflectionof the guidewire 100 towards the third lumen 124 securing guidewire 100to the internal wall 130 and the electromagnet 126. The guidewire 100may then be moved in the proximal direction to deflect the leadingcatheter end segment 128 in the same manner as shown in FIG. 8. Torelease the guidewire 100, the electromagnet 126 may be deactivated. Theelectromagnet 126 may be selectively activated and deactivated toprovide selective engagement of the guidewire 100 to the leadingcatheter end segment 128. In embodiments, the electromagnet 126 may bereplaced with a permanent magnet.

FIG. 18 illustrates another embodiment of the present disclosure. Inaccordance with this embodiment, the catheter 14 includes three lumens,namely, device lumen 140 and first and second guidewire lumens 142, 144.The first and second guidewire lumens 142, 144 each may receive aguidewire 100. Each guidewire lumen 142, 144 also includes fasteningstructures, identified schematically as reference numerals 146, 148,respectively, for selectively engaging the guidewires 100. The fasteningstructure may include any of the aforedescribed arrangements describedin connection with the embodiments of FIGS. 1-17. With the dualguidewire and fastener arrangement, different sections 150, 152 of theleading catheter end segment 154 may be secured and thus selectivelydeflected through corresponding movement of the guidewires 100 withinthe guidewire lumens 142, 144. For example, during the procedure, theclinician may desire to initially deflect the distal section 150 of theleading catheter end segment 154. The fastening structure 146 associatedwith the distal section 150 is activated securing the guidewire 100relative to the distal most section 150. The distal section 150 is thendeflected in the aforedescribed manner. When it is desired to deflectthe second or proximal section 152 of the leading catheter end segment154, the fastener structure 148 is activated securing the guidewire 100adjacent this section 152. The guidewire 100 is manipulated to deflectthe proximal section 152. In embodiments, the proximal and distalsections 152, 150 may be deflected in different, e.g., opposeddirections relative to the longitudinal axis as depicted by thedirectional arrows “y”, “z”. In other embodiments, the proximal anddistal sections 152, 150 may be deflected in the same direction. Otherarrangements are also envisioned.

FIGS. 19-20 illustrate another embodiment of the present disclosure. Inaccordance with this embodiment, the catheter member 14 includesguidewire lumen 170 and device lumen 172. The guidewire 100 may have alooped segment 102 at its distal end. The looped segment 102 may beformed and tied off by the clinician at the treatment site. The cathetermember 14 may further include at least one or more inwardly dependingdetents 174 within the guidewire lumen 170. The locking detents 174 maybe molded with the catheter member 14 during manufacture or be aseparate component(s) secured to the catheter member 14 throughadhesives and/or cements. In use, the catheter 14 is advanced along theguidewire 100. When it is desired to deflect the leading catheter endsegment 176, the guidewire 100 is retracted or pulled in a proximaldirection until the looped segment 102 engages the detents 174 wherebyupon engagement therewith, the looped segment 102 and the catheter 100are secured relative to the leading catheter end segment 176, i.e.,achieving a secured condition depicted in FIG. 19. Further movement ofthe guidewire 100 in a proximal direction when in the secured conditionwill deflect the leading catheter end segment 176 in the mannerdiscussed hereinabove.

FIGS. 21-22 illustrate another embodiment of the present disclosure. Inaccordance with this embodiment, the leading catheter end segment 180includes internal locking structure 182 which may be at least one wall,detent, and/or surface of predefined geometry extending within the lumen184 of the leading catheter end segment 180. The guidewire 100 includeslocking element 106 which generally corresponds to the opening 186 inthe predefined geometry of the locking structure 182. To initiallyadvance the guidewire 100 relative to the leading catheter end segment180, the lock element 106 is generally aligned with the opening 186 ofthe locking structure 182 to permit passage of the guidewire 100 throughthe lumen 184. When it is desired to secure the guidewire 100 relativeto the leading catheter end segment 180, the guidewire 100 is rotatedthrough an arc of rotation “v”, e.g., 90 degrees about the longitudinalaxis “k”, to displace the lock element 106 relative to the lockingstructure as shown in FIG. 22 (note the release or aligned position ofthe lock element 106 relative to the locking structure 182 is shown inphantom). In this secured position, the leading catheter end segment 180may be deflected through longitudinal movement of the guidewire 100 asdiscussed hereinabove. When it is desired to release the guidewire 100,the guidewire may be rotated 90 degrees in the opposite direction toalign the lock element 106 with the opening 186 in the locking structure182 (760 millimeters) 100 and the leading catheter end segment 180. Theguidewire 100 may be selectively secured and released relative to theleading catheter end segment 180 during use of the system 1.

FIG. 23 is a flow chart depicting an exemplary method of use of thesystem 1 in performing a surgical procedure and In accordance with oneexemplary procedure 200, the vasculature is accessed (STEP 202) by,e.g., introducing a hollow needle into an artery or vein via apercutaneous procedure. The guidewire is introduced within the needleand advanced to a location proximate a targeted site. (STEP 204). Thecatheter 10 is then introduced and advanced along the guidewire 100(STEP 206) to position the leading catheter end segment 28, 38, 92, 128,154, 176, 180 adjacent the targeted site. Any of the aforedescribedselective engagement mechanisms may be utilized to secure the guidewire100 relative to the leading catheter end segment 28, 38, 92, 128, 154,176, 180 of the catheter member (STEP 208). The leading catheter endsegment 28, 38, 92, 128, 154, 176, 180 is deflected by pulling on theguidewire in a proximal direction (STEP 210) to facilitate furtheradvancement of the catheter 10. It is envisioned that the leadingcatheter end segment 28, 38, 92, 128, 154, 176, 180 may be selectivelysecured and released relative to the guidewire 100 during advancement.An interventional procedure is performed (STEP 212) by introducing adevice through a device lumen of the catheter to access vasculature andtreatment sites. Examples of procedures contemplated include, but arenot limited to introducing a stent, deploying, a flow diverter deviceacross an arteriovenous malformation (AVM) or an aneurysm, deploying aflow restoration device to capture an occlusion, and/or introducingembolic coils or an embolic solution into an aneurysm.

It is to be appreciated that the disclosure has been describedhereinabove with reference to certain examples or embodiments of thedisclosure but that various additions, deletions, alterations andmodifications may be made to those examples and embodiments withoutdeparting from the intended spirit and scope of the disclosure. Forexample, any element or attribute of one embodiment or example may beincorporated into or used with another embodiment or example, unlessotherwise specified to do so would render the embodiment or exampleunsuitable for its intended use. In addition, the catheter member 14 maybe a single lumen catheter where each of the disclosed embodiments oflocking mechanisms or fastener structure is disposed within the singlelumen. All reasonable additions, deletions, modifications andalterations are to be considered equivalents of the described examplesand embodiments and are to be included within the scope of the followingclaims.

What is claimed is:
 1. A catheter system, which comprises: an elongatecatheter defining a longitudinal axis and defining a lumen extending atleast partially therethrough, the catheter comprising a leading catheterend segment; a guidewire positionable within the lumen of the catheter,the guidewire and the catheter being adapted for relative movement; anda fastening structure within the lumen of the elongate catheter andsupported adjacent the leading catheter end segment, the guidewireextending through the fastening structure, wherein the fasteningstructure is dimensioned to selectively engage the guidewire to securethe guidewire with respect to the leading catheter end segment, andwherein the fastening structure is positioned within the elongatecatheter such that when the fastening structure is engaged with theguidewire, movement of the guidewire causes deflection of the leadingcatheter end segment with respect to the longitudinal axis.
 2. Thecatheter system according to claim 1 wherein the fastening structureincludes a clamp adjacent the leading catheter end segment, the clampmovable between a rest position corresponding to a release condition ofthe guidewire and an actuated position corresponding to a securedcondition of the guidewire where the clamp engages the guidewire in thelumen in secured relation therewith.
 3. The catheter system according toclaim 2 wherein the clamp is at least partially disposed within thelumen of the catheter when the clamp is in the actuated position.
 4. Thecatheter system according to claim 3 wherein the clamp is a grommet, thegrommet defining a passage for reception of the guidewire, the grommetbeing at least partially compressible to engage the guidewire uponmovement to the actuated position.
 5. The catheter system according toclaim 4 wherein the grommet is adapted to move within the lumen from afirst longitudinal position to a second longitudinal position inresponse to introduction of fluids within the lumen.
 6. The cathetersystem according to claim 5 wherein the catheter includes internaltapered surfaces adjacent the lumen, the tapered surfaces cooperatingwith the grommet during movement thereof to the second longitudinalposition to compress the grommet onto the guidewire.
 7. The cathetersystem according to claim 5 including a source of pressurized fluids influid communication with the lumen.
 8. The catheter system according toclaim 1 wherein the fastening structure includes a filament memberextending along the catheter and defining a loop segment, the loopsegment dimensioned to receive the guidewire to secure the guidewirewith respect to the leading catheter end segment.
 9. The catheter systemaccording to claim 8 wherein the loop segment includes a lasso.
 10. Thecatheter system according to claim 1 wherein the catheter includes adevice lumen dimensioned for reception of an interventional device. 11.The catheter system according to claim 1 wherein the guidewire isadapted for one of rotational or radial movement relative to thecatheter to secure the guidewire with respect to the leading catheterend segment.
 12. The catheter system according to claim 1 wherein thelumen comprises a first lumen, the guidewire comprises a firstguidewire, the fastening structure comprises a first fasteningstructure, and the leading catheter end segment includes first andsecond catheter sections, and wherein the first fastening structure isconfigured to secure the first guidewire with respect to the firstcatheter section such that when the first fastening structure is engagedwith the first guidewire, movement of the first guidewire causesdeflection of the first catheter section, the catheter further defininga second lumen, and the catheter system further comprising: a secondguidewire positionable within the second lumen of the catheter, each ofthe first and second guidewires being adapted for relative movementwithin the respective first and second lumens; and a second fasteningstructure dimensioned to selectively engage the second guidewire tosecure the second guidewire with respect to the second catheter section,and wherein the second fastening structure is positioned within theelongate catheter such that when the second fastening structure isengaged with the second guidewire, movement of the second guidewirecauses deflection of the second catheter section.
 13. The cathetersystem according to claim 12 wherein the first catheter section isadapted to deflect in a first radial direction with respect to thelongitudinal axis and the second catheter section is adapted to deflectin a second radial direction with respect to the longitudinal axis. 14.The catheter system according to claim 13 wherein the first radialdirection is different from the second radial direction.
 15. Thecatheter system according to claim 1 wherein the guidewire includes alooped segment, and the fastening structure includes at least one detentdepending into the lumen, the detent positioned to engage the loopedsegment of the guidewire to secure the guidewire with respect to theleading catheter end segment.
 16. The catheter system according to claim1 wherein the fastening structure includes a locking structure ofpredefined geometry within the lumen and the guidewire includes alocking element, the locking element adapted to move between a releasecondition and a secured condition with respect to the leading catheterend segment through relative rotation of the guidewire and the leadingcatheter end segment about the longitudinal axis, wherein in the securedcondition, the guidewire is secured with respect to the leading catheterend segment.
 17. The catheter system according to claim 1, wherein thefastening structure is dimensioned to selectively directly engage theguidewire to secure the guidewire with respect to the leading catheterend segment such that when the fastening structure is engaged with theguidewire, movement of the guidewire causes deflection of the leadingcatheter end segment with respect to the longitudinal axis.
 18. Amedical method, comprising: introducing a guidewire within vasculatureof a subject; advancing a catheter along the guidewire; securing theguidewire relative to a leading end segment of the catheter, whereinsecuring the guidewire comprises securing the guidewire with a fasteningstructure within a lumen of the catheter and supported adjacent theleading catheter end segment, the guidewire extending through thefastening structure, wherein the fastening structure is dimensioned toselectively engage the guidewire to secure the guidewire with respect tothe leading catheter end segment, and wherein the fastening structure ispositioned within the elongate catheter such that when the fasteningstructure is engaged with the guidewire, movement of the guidewirecauses deflection of the leading catheter end segment with respect tothe longitudinal axis; and manipulating the guidewire to causedeflection of the leading end segment of the catheter.
 19. The medicalmethod according to claim 18 wherein securing the guidewire is performedsubsequent to advancing the catheter.
 20. The medical method accordingto claim 18 wherein securing the guidewire includes selectively securingand releasing the guidewire relative to the leading end segment of thecatheter.
 21. The medical method according to claim 18 furthercomprising performing an interventional procedure.
 22. The medicalmethod according to claim 21 wherein performing the interventionalprocedure includes introducing a medical device within the catheter.